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Thread: Belt grinders - where do I start?

  1. #1
    Senior Member Matus's Avatar
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    Question Belt grinders - where do I start?

    Hi,

    I have recently started with stock removal. I am experimenting with both kitchen and outdoor knives, but kitchen knives are more interesting to me. Since currently my only power tool is a drill press, I am grinding the bevels with a file (filing jig that allows me to keep constant angle). While this approach is quite usable with smaller outdoor blades where one neither needs to grind under very acute angles (precision), nor a distal taper is of such an importance, it takes VERY long with kitchen knives where a lot of material needs to be removed to achieve usable grind. Also - after heat treat there is some more material to be removed as the edge could warp if ground thin before heat treat - and that is VERY slow process. I have spend about 6 hours with Atoma 140 with my first kitchen knife (165mm petty/gyuto). Arguably I could have done better job prior to thinning, but still - it will be several hours on Atoma with each kitchen knife.

    My current (and arguably naive) idea is (if my interest in knifemaking will pertain) to make knives part-time (say 10 - 15 hours a week) - maybe in a year or so. I do not plan to become a full time maker, but I would cut down on my normal job working hours to allow for the knifemaking.

    This brought me inevitably to the point where I started to look at belt grinders, even though my current workshop would most probably not allow me to use one because of space limitations, but that is a separate problem I am looking into.

    My questions
    Where I would like to ask for a help is to figure out what features the belt grinder needs to have to be usable for knifemaking. In more detail - what feature/accessory/add-on is used for what purpose.

    Of course - do not hesitate to recommend a belt grinder you have good experience with, but please do that together with the features/qualities that you find important or helpful.

    Side notes
    I am located in Germany and there is to my knowledge 1 belt grinder made locally that is meant for knifemaking is the 2-SF model. So if you are aware of other usable belt grinders within EU I would be interested to know about them.

    Last but not least - of course I am aware of the belt grinder Marko has just started to produce - that seems to be an excellent machine, but I am not yet sure I will be able to afford a grinder in that category (remember - I have shipping and 27% taxes to pay)

    thank you

  2. #2
    Dan P.'s Avatar
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    I found my Norm Coote grinder very competitive in price even after factoring in shipping and import duty. It's a very simple affair, but I only really require the flat platen anyway. I've had it for maybe 7 years, it's pretty sturdy.
    Compared to European made grinders the KMG is also very competitive. If I were to buy a new grinder now I might consider a KMG. The shipping cost would be pretty monstrous as they are very heavy machines, but even then, in the balance still a good deal.
    Again, the makers of KMG "clones" in Europe suffer from very long waiting lists, too.
    Lastly, I'm sure such things must be available in Germany, but second-hand belt grinders do turn up on ebay from time to time, if you are patient.

    PS Thinking about it even the wide belt wood sanding machines are better than nothing and can usually be picked up second hand for a song.

  3. #3
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    I've owned two Cootes (48" and 72"), a Bader B2, a Wilton square wheel, a VanSant Multitool, a KMG, and I've built my own three times. I kept the KMG and, because I have the space to spare, my home-built Frankengrinder. Dan is right, even with shipping a Coote is probably the most reasonable new grinder you'll find. The Coote is well built and would serve you for years. If you can locate something used that fits your needs, then you should buy it! I find I'm happiest when I have a lot of accessories, but, realistically I could get by with a machine that has a flat platen (Coote)...that allows flat grinding and profiling, with a little slack belt above or below the platen for convexing or softening hard edges. The Coote also tilts back to expose the bottom contact wheel, which can be used for some hollow grinding or curves. Finishing off complex shaping can be done with files or dowels wrapped with abrasives. Speed can be variable via stepped pulleys or a variable speed controller.
    -Mark

  4. #4
    Senior Member Castalia's Avatar
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    This is a thread where I got some good advice:

    http://www.kitchenknifeforums.com/sh...der?highlight=

    I still have not decided to purchase one yet, as my latest project has been building a work bench for the garage with hand tools. The baby Wilmot seemed like a good possibility for me, but I cannot speak to shipping to Germany.

  5. #5
    Senior Member Matus's Avatar
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    Thanks, let me add a few questions These are mostly based on a KMG grinder as theit webpage has a lot of clear photos of the setups and acccessories.

    The bottom line for the questsions below is to figure out what I may need from the grinder (must have or nice to have). Once I will be buying one I will most probably get the whole package from US including all necessary parts and accessories.

    Speed:
    - How much of a limitations is single speed?
    - How much of a hassle is to switch a drive belt? Variable speed unit costs $300-$500 extra, is it worth it?

    Wheels:
    - What is the advantage of larger wheel (say 12" or 14") over a smaller one?
    - How relevant is the size of the drive wheel (apart from the effect on the belt speed)?

    Moto
    - is 1.5hp enough or should one go to at least 2hp?
    - can the direction of the roation of the belt be swapped with every motor - i.e. - is it just a question of the control unit or is it a matter of motor construction?yy

    Acessories:
    - which add-ons beyond large contact wheel and platen do you use for what purpose?
    - in particular - to get a convex grind on a kitchen knife - does the small wheel attachment and thus the ability to have the belt running nearly horizontal helps?

    Belts:
    - what are the good quality belts (makes, models)?
    - what grits do you use for what purpose?
    - how long do the different belts last?

    thanks

  6. #6
    Senior Member Castalia's Avatar
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    Remember electrical considerations for an American 120v motor running on 220v German power. Most U.S. and Canadian power tools are built for 110-120 v, and would likely require a step-down voltage transformer as well as a plug adapter. That's setting aside the single phase (home) outlet vs three phase (industrial) outlet for bigger motors. I don't know how a variable speed motor control with work with all that as well. Probably a good idea to talk to the manufacturer and a local electrician.

  7. #7
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    If you are just doing heavy stock removal (profiling and initial bevels), single speed may not be a big deal...but when you go into grinding details, speed control keeps you from those "Oops moments". I've read a lot of forum posts over the years by folks who say that they can't believe they ever got along without variable speed. I wouldn't give mine up. Drive belts aren't difficult to change as long as you design the belt/motor/pulley setup to be easily changed. If that's the route you go, try to find a pulley with as many pulley slots as you can so as to get as many speeds out of it as possible.

    Larger contact wheels allow a shallower/taller hollow grind....great for things like Japanese grinds and razors. Apart from belt speed, the only thing I can think of that drive wheel size would affect is grinding belt length/accessory adjustment.

    A well made motor at 1.5hp is great....2hp is better, but it isn't a necessity. Just a few years ago the question was, "Do I need more than 3/4hp?". Not every motor is easily reversible, but if you go with 3 phase and a controller then there's nothing to worry about. Reversibility is not something that everybody needs or wants in a belt grinder. I have my dust collector mounted below the belt as it runs in the forward direction. If I reverse it, then I'm throwing grinder grit and steel dust all over the place.

    As for add-ons, I use a KMG rotary platen occasionally for convexing, and I've made my own small wheel attachment for finger grooves and tight handle curves. I suppose you could use the slack created by using a small wheel, but the bearings in a small wheel are prone to burning up at high speed, so it would be slow going. It's safer just to remove the platen and use the slack created by that.

    Belts are a tricky subject. I like 3M Trizact, and almost anything Norton makes. Ceramics are great and last a while. Some folks use a progression of 5 or 6 belts....some folks use 2! I think most just experiment until a combination that pleases occurs. I'm all over the place and have no set progression.

    -Mark

  8. #8
    Senior Member Matus's Avatar
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    You guys are awesome, please keep it coming

  9. #9

    JBroida's Avatar
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    i would never buy a belt grinder without speed control (variable speed or step pulleys) ever again now that i have one

  10. #10

    Marko Tsourkan's Avatar
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    Quote Originally Posted by Castalia View Post
    Remember electrical considerations for an American 120v motor running on 220v German power. Most U.S. and Canadian power tools are built for 110-120 v, and would likely require a step-down voltage transformer as well as a plug adapter. That's setting aside the single phase (home) outlet vs three phase (industrial) outlet for bigger motors. I don't know how a variable speed motor control with work with all that as well. Probably a good idea to talk to the manufacturer and a local electrician.
    If you use a VFD that is 50/60Hz and is 230V compatible, you can use it in the US and Europe, with either 50Hz or 60Hz 3 phase motors. You set the motor frequency on the VFD and just attach a plug that uses in your country.

    The power of a larger motor comes handy if you grind taller blades, particularly if you do flat grinds. I can stall my 2HP motor (1.5HP on 115V) while flat grinding a tall blade in no time. 230V and 2+ HP is the way to go for this particular task.

    Getting a grinder without VFD is something that you will most likely regret down the road. As you are thinning your blank and getting to .5mm on the edge, you need to slow down the belt speed, or you might burn the edge, and would need to grind out your burn spot - reprofile and make a smaller knife. You can't hide it, the burr formation in that spot will give it away.

    3M and Norton are considered the top dogs among belts, with Klingspor, Hermess and other makers are considered budged. 36 grit will remove metal the fastest, but will also leave deepest scratches. I grind with 36, then 80, then 120, 220 then polish by hand with automotive sand paper. If you plan on doing a machine polish, Norton and 3M make excellent polishing belts.


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